MDMA的神经毒性及SERT mRNA的表达

目的 :探讨MDMA的神经毒性及SERTmRNA的表达。方法 :设立对照组和实验组 ,实验组给予MDMA(2 0mg·kg- 1 ,每日 2次 ,ip ,连续 4d) ,对照组给予等体积生理盐水。采用高效液相色谱法测定不同脑区的DA和 5 -HT含量 ,原位杂交方法检测SERTmRNA的表达。结果 :给予MDMA后 ,大鼠额叶皮层、海马和纹状体的 5 -HT下降 (P <0 0 0 1) ,SERTmRNA的表达明显减少 (P <0 0 0 1)。结论 :MDMA对中枢 5 -HT系统有明显的神经毒性 ,导致SERTmRNA表达下调。     

An in vitro approach to assessing a potential drug interaction between MDMA (ecstasy) and caffeine

3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is a popular recreational drug which causes long-term neurotoxicity and increased risk of fatality. In rats, MDMA toxicity is exacerbated by co-administration of caffeine. The aim of this study was to investigate whether caffeine altered the effects of MDMA in a battery of in vitro tests selected to model some of the known actions of MDMA in vivo. In cytotoxicity studies, caffeine modestly enhanced the effect of MDMA on neuronal N2a cell viability but not that of liver, intestinal or kidney cells. MDMA inhibited the formation of fluorescent metabolites by CYP2D6 ≫ CYP3A4 > CYP1A2 but this was not altered by caffeine. Similarly, the inhibition of synaptosomal [³H] 5-HT uptake by MDMA was not affected by the presence of caffeine. Thus, these in vitro tests failed to detect any substantial interaction between caffeine and MDMA, highlighting the difficulty of modelling in vivo drug interactions using in vitro tests. However, the results show that the inhibition of synaptosomal [³H] 5-HT uptake by MDMA was greater at 41 °C and 25 °C than at 37 °C which raises the possibility that MDMA’s effect on SERT in vivo may be increased as body temperature increases, contributing to its harmful effects in users.     

Partial regulation of serotonin transporter function by γ-synuclein

Human α-synuclein (α-Syn) is instrumental in maintaining homeostasis of monoamine neurotransmitters in brain, through its trafficking, and regulation of the cell surface expression and, thereby, activity of dopamine, serotonin and norepinephrine transporters. Here we have investigated whether other members of the synuclein family of proteins, γ-synuclein (γ-Syn) and β-synuclein (β-Syn) can similarly modulate the serotonin transporter (SERT). In Ltk⁻ cells co-transfected with SERT and γ-Syn, γ-Syn reduced [³H]5-HT uptake, in a manner dependent on its expression levels. The decrease in SERT activity was via decreased V_max of the transporter, without change in K_m, compared to cells expressing only SERT. By contrast, β-Syn co-expression failed to alter SERT uptake activity, and neither the V_max nor the K_m was changed in the presence of β-Syn. γ-Syn modulation of SERT was only partial, with a maximal ∼27% decrease in SERT activity seen even at high expression levels of γ-Syn. By contrast, α-Syn attenuated SERT activity by ∼65% at identical expression levels as γ-Syn. Co-immunoprecipitation studies showed the presence of heteromeric protein:protein complexes between γ-Syn or α-Syn and SERT, while β-Syn failed to physically interact with SERT. Both α-Syn and γ-Syn colocalized with SERT in rat primary raphae nuclei neurons. These studies document a novel physiological role for γ-Syn in regulating 5-HT synaptic availability and homeostasis, and may be of relevance in depression and mood disorders, where SERT function is dysregulated.     

Serotonin transporter polymorphism modifies the association between depressive symptoms and sleep onset latency complaint in elderly people: results from the ‘InveCe.Ab’ study

Previous studies have documented the involvement of the central nervous system serotonin in promoting wakefulness. There are few and conflicting results over whether there is an actual association between bearing the short allele of serotonin transporter promoter polymorphism (5‐HTTLPR) and worse sleep quality. This study examined whether sleep onset latency complaint is associated with the 5‐HTTLPR triallelic polymorphism in the SLC6A4 gene promoter and whether this polymorphism influences the relationship between sleep onset latency complaint and depressive symptoms in elderly people. A total of 1321 community‐dwelling individuals aged 70–74 years were interviewed for sleep onset latency complaint and for sleep medication consumption. Participants’ genomic DNA was typed for 5‐HTTLPR and rs25531 polymorphisms. Depressive symptoms were evaluated with the Geriatric Depression Scale Short form and general medical comorbidity was assessed by the Cumulative Illness Rating Scale. The presence of a past history of depression was recorded. The S′ allele of the 5‐HTTLPR triallelic polymorphism was associated with sleep onset latency complaint. This association was maintained after adjusting for depressive symptoms, sex, age, history of depression and medical comorbidity. After stratification for 5‐HTTLPR/rs25531, only in S′S′ individuals high depressive symptoms were actually associated with sleep onset latency complaint. These data indicate that the low‐expressing 5‐HTTLPR triallelic polymorphism is an independent risk factor for sleep onset latency disturbance. Furthermore, the 5‐HTTLPR genotype influences the association between depressive symptoms and sleep onset latency complaint.     

Molecular defects in mucosal serotonin content and decreased serotonin reuptake transporter in ulcerative colitis and irritable bowel syndrome

BACKGROUND & AIMS: Serotonin (5-HT) is a critical signaling molecule in the gut. 5-HT released from enterochromaffin cells initiates peristaltic, secretory, vasodilatory, vagal, and nociceptive reflexes. Despite being pathophysiologically divergent, ulcerative colitis (UC) and irritable bowel syndrome (IBS) are both associated with clinical symptoms that include alterations in the normal patterns of motility, secretion, and sensation. Our aim was to test whether enteric 5-HT signaling is defective in these disorders. METHODS: Rectal biopsy specimens were obtained from healthy controls and patients with UC, IBS with diarrhea (IBS-D), and IBS with constipation (IBS-C). Key elements of 5-HT signaling, including measures of 5-HT content, release, and reuptake, were analyzed with these samples. RESULTS: Mucosal 5-HT, tryptophan hydroxylase 1 messenger RNA, serotonin transporter messenger RNA, and serotonin transporter immunoreactivity were all significantly reduced in UC, IBS-C, and IBS-D. The enterochromaffin cell population was decreased in severe UC samples but was unchanged in IBS-C and IBS-D. When 5-HT release was investigated under basal and mechanical stimulation conditions, no changes were detected in any of the groups relative to controls. CONCLUSIONS: These data show that UC and IBS are associated with similar molecular changes in serotonergic signaling mechanisms. While UC and IBS have distinct pathophysiologic properties, these data suggest that shared defects in 5-HT signaling may underlie the altered motility, secretion, and sensation. These findings represent the first demonstration of significant molecular alterations specific to the gut in patients with IBS and support the assertion that disordered gastrointestinal function in IBS involves changes intrinsic to the bowel.     

痛泻安脾汤对腹泻型肠易激综合征大鼠5-羟色胺、5-羟色胺转运蛋白的影响

目的:观察痛泻安脾汤对腹泻型肠易激综合征(diarrhea irritable bowel syndrome,IBS-D)模型大鼠5-羟色胺(5-hydroxytrypta mine,5-HT)、5-羟色胺转运蛋白(serotonintransporter,SERT)影响。方法:48只雌雄各半的SPF级SD大鼠进行适应性饲养1周后,遵循随机原则将大鼠分为正常组12只,造模组36只(模型组、中药组、西药组),每组各12只,采用束缚+番泻叶灌胃法建立IBS-D肝郁脾虚证模型。造模成功后,正常组、模型组给予生理盐水灌胃,西药组给予阿洛司琼溶液,中药组给予痛泻安脾汤灌胃。酶联免疫吸附法检测血清5-HT水平,免疫组织化学法检测结肠组织、脑组织中5-HT、结肠组织SERT水平,Western blot法检测结肠组织中5-HT蛋白的表达。结果:血清5-HT水平比较:与正常组大鼠血清5-HT水平比较,模型组大鼠血清5-HT水平升高明显(P<0.05);与模型组大鼠大鼠血清5-HT水平比较,中药组、西药组均明显降低,差异有统计学意义(P<0.01)。结肠组织Western blot检测结果比较:与模型组大鼠大鼠比较,中药组、西药组大鼠结肠5-HT蛋白表达显著降低(P<0.01);与正常组大鼠比较,模型组大鼠结肠5-HT蛋白表达水平升高(P<0.01)。结肠和脑组织(5-HT)免疫组织化学结果比较:与正常组大鼠比较,模型组大鼠5-HT水平升高明显(P<0.01);中药组、西药组血清5-HT水平显著低于模型组(P<0.01)。结肠免疫SERT结果比较:在模型组大鼠肠黏膜中SERT呈低表达状态,且显著低于正常组(P<0.01);中药组、西药组大鼠肠组织SERT表达水平显著高于模型组(P<0.01)。结论:痛泻安脾汤能够调节IBS-D大鼠5-HT、SERT水平,缓解腹痛、腹泻、腹胀等不适症状。     

Polymorphisms in the serotonin transporter protein (SERT) gene in patients with pulmonary arterial hypertension

Serotonin is a potent vasoconstrictor and pulmonary vascular growth factor whose concentration is increased in patients with pulmonary arterial hypertension (PAH). Its functions are mediated in part by the serotonin transporter protein (SERT) whose gene can have two allelic forms, both long (L) and short (S). The first was associated with greater function.     

Common and rare alleles of the serotonin transporter gene,SLC6A4, associated with Tourette's disorder

To evaluate the hypothesis that functionally over‐expressing alleles of the serotonin transporter (SERT) gene (solute carrier family 6, member 4, SLC6A4) are present in Tourette's disorder (TD), just as we previously observed in obsessive compulsive disorder (OCD), we evaluated TD probands (N = 151) and controls (N = 858). We genotyped the refined SERT‐linked polymorphic region 5‐HTTLPR/rs25531 and the associated rs25532 variant in the SLC6A4 promoter plus the rare coding variant SERT isoleucine‐to‐valine at position 425 (I425V). The higher expressing 5‐HTTLPR/rs25531 L_A allele was more prevalent in TD probands than in controls (χ² = 5.75; P = 0.017; odds ratio [OR], 1.35); and, in a secondary analysis, surprisingly, it was significantly more frequent in probands who had TD alone than in those who had TD plus OCD (Fisher's exact test; P = 0.0006; OR, 2.29). Likewise, the higher expressing L_AC haplotype (5‐HTTLPR/rs25531/rs25532) was more frequent in TD probands than in controls (P = 0.024; OR, 1.33) and also in the TD alone group versus the TD plus OCD group (P = 0.0013; OR, 2.14). Furthermore, the rare gain‐of‐function SERT I425V variant was observed in 3 male siblings with TD and/or OCD and in their father. Thus, the cumulative count of SERT I425V becomes 1.57% in OCD/TD spectrum conditions versus 0.15% in controls, with a recalculated, family‐adjusted significance of χ² = 15.03 (P < 0.0001; OR, 9.0; total worldwide genotyped, 2914). This report provides a unique combination of common and rare variants in one gene in TD, all of which are associated with SERT gain of function. Thus, altered SERT activity represents a potential contributor to serotonergic abnormalities in TD. The present results call for replication in a similarly intensively evaluated sample. © 2013 Movement Disorder Society     

Clobenpropit,a histamine H3 receptor antagonist/inverse agonist,inhibits [3H]-dopamine uptake by human neuroblastoma SH-SY5Y cells and rat brain synaptosomes

Background

Clobenpropit, a potent antagonist/inverse agonist at the histamine H₃ receptor (H₃R), reduced the cytotoxic action of 6-hydroxydopamine (6-OHDA) in neuroblastoma SH-SY5Y cells transfected with the human H₃R. We therefore set out to study whether this effect involved a receptor-independent action on dopamine transport.

Binding-Induced Fluorescence of Serotonin Transporter Ligands: A Spectroscopic and Structural Study of 4-(4-(Dimethylamino)phenyl)-1-methylpyridinium (APP+) and APP+ Analogues

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